Telephone system



Oct. 29, 1929. R. E. coLLls TELEPHONE SYSTEM Filed Sept. 19. 1928 2 Sheets-Sheet l Illu).

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Cet. 29, 1929.. R, E C'oLLls 1,733,580

'TELEPHQNE SYSTEM Y Filed Sept. 19. .1928 2 Sheets-Sheet 2 V V DI..

V D-n /NVENTDR t RECou/a ATT/VVEY *tem shown in Fig.y 1. f

Patented Oct. 29, 1929 WA1,733,58e

UNITED `stares PATENT OFF,

.RAYMOND E. -GOLLIS, 0F' EAST ORANGE, NEVI' JERSEY, .ASSIGNOVR T0 BELL 'TELEPHONE y LABORATORIES, NCORPORATED, AOF NEW YORK, N'.y Y., CORPORATION OFfNEW YORK TELEPHONE SYSTEM Application filed September 19, 1928. Serial No; 306,811.

rlfhis invention ,relates to telephone systems and particularly yto improvements in part-y line ymessage registration.

The object is to enable the performance of a more positive and reliable `test of party lin-es to identity the station originating the call.

A feature off `the. invention is a system in which the substations on a party line are equipped with devices which permit the How .ot current in one direction, but oder substan- -tial resistance to flow inthe opposite di 'rection, the ldevices aty a plurality oi said substations being connected in series with the talking circuit.

Another feature is a' testing arrangement at ythe central oilice by means of which a number of preliminary `tests are made to partially establish the identity of `the ycalling station, following which Zone of a number of yiinal tests is made, dependent on the results of the preliminary tests,-to completely identify said calling station.r

In the drawing,f]i`ig.v 1 illustrates a party line in an automatic telephone system arranged for testing yand message registration in accordance with the features ot this'invention. Fig.2 is a modiiication of the sys- The subscribers line L, shownin Fig.` 1, is provided with four .substationsin B, U and D. All tour of these substations are equipped with' unidirectional current `'carrying devices 'connected in diii'erent ways to enable a d1stinctive test todetermine the calling substation. These devices, being unidirectional or asymmetrical, permit current to flow in one direction, but resistthe flow of current in the opposite direction; At stations A and B the unidirectional devices 1 and Saro connected in series with impedance `coils`21and 4, respectively, to a contact of the receiver switchhoolr in such a manner that current of negative polarity is permitted to flow from* the line through the coils 2 and 4 and the devices 1 and 3 to ground. At stations C and D the devices 6 and 8, included in series, re-

Ispectivelywith coils 7 and 9, are connected in the opposite direction so that current of positive polarity'ispermitted to How from AMarch 2.8, 1916, and in thepatent to Craft the line to ground. Atgstation B the device @5 f is connected in the tip side of the talking circuit to permit current of positive polarity to ilow i'rom the tip side of theline through .the tele-phone set, but to resist the' flow of negative current. yA t the substation D the device 10 is connected as shown kin the talking circuit so that current of `negative polarity .is

permitted to flow from the yring side yofthe ine through said device, but current of opp0 site polarity is prevented from flowing.y The uni-directional current devices may be of 'any suitable type such as ldescribed in the'Journal of the `American Institute ofElectrical'Enf i i i gineers for March 1927, page 215.. f -'lhe line L extends to the central office 'and terminates in the Contact bank of aline indf er switch F, which is' illustrated vschematically by the brushes l1 to 16 inclusive. The

rline iinderF extends the line to the brushes@r ci a yselector,switch S also shown "schematiy cally.y The line finder F and selectors may be of any suitable type such vas the power driven panel type switches described in the patent to McQuarrie, No. 1,177 ,044, granted et al,'No. 1,123,696, grantediJan. 5, 1915. The selector `S A,and succeeding selector switches may be controlled by central oilice register senders, such as described in detail :go in the patent to Kopp, No. 1,589,402, granted J une 22, 1926 and the patent to Stearn et al, No. 1,395,977, granted Nov; 1, 1921.

f Since each' of the four substationsis provided with an individual message register at 35 the central office, (registers 34A to 37) it is necessary to make `a test of the line at some yconvenient time `to determine which substationhas initiated'the call. By using` annilateral device of the character described, a more dependable and yaccurate test is pos-y sible for the ,reason that these devices are `included directly Ain series withthe talking with yrelays 2G and 27 and oppositelypoled 100.y

sources and 41. rlhe test is divided into two parts, the first or preliminary test serving to determine which pair ot stations is responsible fortlie call The second or iinal test is made by the relays 26 and 27 and depends upon the outcome ot the iirsttest and serves to accurately determine which one ot the pair or" substations initiated the call.

" Taking up the detailed description, it will first be'assuined that a callis originated at the substation A. The initiation of the call sets the line finder F in operation to iind the Calling subscribers line. Following this the calledline designation is sent by the impulse transmitter and recorded at the central ofce for the purpose of operating the switch S and succeeding switches to complete the extension of the connection to the called line rt some convenient point in the extension oi the connection the controlling sequence switch 25, associated ywith the switch S and finder F, reaches some position such as position 12. As soon, after the sequence switch reaches posi tion 12, as the power driven interrupter 23 closes its upper contact, a Ycircuit is completed from ground `through the vcontact ot said interruptor, sequence switch spring` 29, left back Contact of relay 20, lower winding or relay 17 to battery. Relay 17 operates and 'locks through its upper winding Yand contact to ground at the contact oit' spring 28. With relay 17 actuated, the tip and ring conductors of theline L are extended through the brushes VA11 and 12, frontV contacts otrelay 17, back contacts of relays 18 and 19, conductor -outer right back contact of relay 20,1eft wind- Ying of test relay 21, to the negative pole of battery 38. r,his test circuit, it will be noted, includes both the tip and ring conductors of the line L. Atl the substation A the tip conductor extends through the winding ot' the induction coil, the switchhool contacts, the coil 2 to the device 1. Since the polarity of the source 38, applied to the tip conductor, is negative, current is permitted toilowthrough the device 1 to ground and thence to the opposite pole ol battery 38. In like manner a circuit may be traced over the ring vside of the line through lthe impulse transmitter and talking transmitter and thence through the coil 2 and device V:1 to ground. Wit-h current ilowing in the test circuit relay 21 operates, and it locks `through its right winding and contact .to Vground at the sequence switch spring 31.

TWhen interrupter 23 shifts its contact-s, a

circuit is com aleted from Oround through theV lower contact ofthe interruptor, lower trent contact of relay 17, lowerbaclr contact or relay 18, .lett windingY ot relay 20 to battery. Relay 2O operates and it locks through its right winding and contact to vthe sequence switch spring 28.,V Relay .20:disct'innec'ftsthe test conductor 44 from the y,relay 21 and connects it to the test-.relay 22. Thetest circuit now rextends from the positive upper contacts ot the interrupter, sprino- 29, lett front contact or" relay 20, outer left back contact ot relay 22, middle right Contact of relay 21, lower winding ot' relay 19 to battery. Relay 19 operates and locks through its upper winding and contact to the sequence switch spring 28. Relay 19 opens the preliminary test circuit above described and closes the tip side of the line to the conductor 45, thus establishing a second test circuit. This second test circuit may be traced from the negative pole of battery 40, through the lower winding of test relay 26, conductor 45, upper front contact oi' relay 19, upper back contact ot relay 18, upper front contact of relay 17, thence over the tip side of the line through the coil 2 and the device 1 to ground. rlhe potential being of the proper polarity, current flows in this circuit and operates the relay 26. Relay 26 locks through its upper winding and contact to ground at the sequence switch spring 31` Later, the interrupter 23 shifts its contacts and a circuit is completed from ground through the lower contacts of the interruptor, inner lower contact of relay 17, lower front contact or relay. 19, through the spring 43 tov the sequence switch magnet 25. `Thus, the sequence switch advances into some subsequent position indicating that the test has been conipleted. As the sequence switch Vmoves out of position 12, the holding circuits of relays- 17, 19 and 20 are opened and these relays'release.

lfthe call is successful and the called sub scriber answers, a. supervisory relay such as the relay 32 operates and completes a circuit from ground through the spring 33, Contact of relay 32, right winding of relay 24 to battery. Relay 24`operates and looks through lits left winding and contact to ground through theV spring 31. Subsequently, when conversation is completed and release is taking place, :the sequence switch 25 moves through successive positions, such as positions '15 to 17. lWhile the sequence switchris Inov- CTI `If the call is initiated at the substation B instead of substation A, the, relay 21 operates on the preliminary test thek same as it did in the instance above described. The operating circuit of rela 21 extends over'the ring side of the line t rough the transmitters and switchhook at the station B, through the coil 4k and the device 3 to' ground. The polarity of the source 38 being negative, current flows and relay 21 operates. Subsequently, when relay 26 is connected to the line as above described, the potential of source being nega'- tive, current will not flow through the tip side of the line due to the device 5, nor through j the ring side due to the device 3. Accordingly, no current flows in the test circuit and re'- lay 26 remains inert. The metering circuit may nowbe traced from battery through the resistance 42, spring 30, outer right front Contact yof relay 21, inner lett back contact of relay 22, upper back contact of relay 26, brush 15, through the register 35 to ground.

Assume next that the Ycall is initiated at the substation C. The iirst test isfmade by connecting the left` winding of relay 21 to the tip and ring conductors, as explained. Since the polarity of the source 38 is negative, current does not How through the device y6 to ground.` Accordingly, relay 21 does not operate. The next test is made by connecting the left winding ofrelay 22 tothe tip and ring conductors, as 'above described. Since the polarity of source 39 is positive, current flowsthroughboth tip and ring conductors through the coil 7 and the' device6 to ground. Relay 22 operates in this circuit and locks through its right winding and/contact to the sequence ,switch spring 31. It will be recalled that when relay 21 operated during the first test a circuit was completed for rela 19 to bring about thesecond portion of tie test, usingfrelay 26.* In rthe present instance, however, since relay 21 is deenergized and relay 22 is operated, acircuit is completed for the re-y lay 18 which may be traced from battery, through the lowerwinding of said relay, left bach contact of relay 2l, outer left front con-` tact of relayl 22 and thence to ground, as above traced. `Relay 18 operates and locks through its upper winding and contact to the spring 28. Under these conditions the second fportion of the test, namely, to 'distinguish whether substation C or substation D is calling, is made by connecting the test relay 27l to the ring side Aof the lineL. rThe circuit may be traced from the positive pole oit' battery 41, lower winding `of relay 27, lower iront contact ot relay18low`,er front contact ot' relay 17 ,thence over the ring side of the line to the transmitters at they substation C, switchhool contact, coil 7, device'6 toground.r Current flowing in this circuit operates the relay 27 which locks through its upper winding and contact to the spring 31. n f f At the end of conversation, the 'metering circuit is closed from battery through therey y sistance 42, contact of relay 24, spring 30, outer right back contact of relay 21, middle contact of relay 22, upper front contact of relay 27, brush 14, register 36 to ground. The register 36 charges the call to the substation C.

` Should the substation D initiate a call, the

test relay 21, on being connected to the tip and ring conductors of the line, does not operf ate for the reason that current o'l' negative po-r larity cannot -tlow over either the tip side or the ring side of the linek due to the devices 8 and 10. Relay 22 on being connected to the line, however, operates since current of positive polarity is permitted to flow over the tip sidesof the line through the coil 9 and device 8 to ground.

soy

Later, when ythe relay27 is connected to The first test, made by the relays 21 and 22, isy

to determine whether the lcall is made by station A or B or by station C or D. .According to which pair of stationsr contains the calling station, a subsequent test is made using either the'relay 26 or the relay 27.` It the calling station is either stationk A or B, then relay'26 is used for the second part of the test and opioo y crates or not accordingto which one of the two stations initiates the call. y0n the other hand, if either station C yor D is calling, relay 27 is used and operates or not according to they calling station. n f f i In Fig. 2 the calling line L-,l has iour substations A-1,B*1, C-l and D 1 provided with unilateral devices the same as those .shown in Fig. 1.5 Devices 48, 50, 53 and 55 are connected in series with coils 49, 5l, 54 and 56, respectively, tok the switchhook contacts and with the poles arranged the saine as shown in Fig. 1. Likewise the device 52 at substation B-1 1s connected in the tip sidethe same as device 5 in Fig. 1." At substation D--1, however, the device 57 is connected in.r

.the tip side of the line in the talking'circuit instead of in the ring 'side as shown at the cor-` responding station in Fig.y 1.

elusive. The `inder F-1 is associated with selector switch S441, which selector and suc- Fig. 1.

Theline L`1 terminates in the contacts of y ythe finder F-1 having brushes `58 to 63, in,

During the establishmentofthe 'connection' T the sequence switch 70 reaches some position,

such as position 12. As soon, after the sequence 4switch reaches position12as the in'-y terrupter 69 closes its upper contacts, a'circuit is closed troni ground through the interrupter,'spring 73, lett back lContact of relay 66, lowerwinding of relay 6st to battery. 6st operates and locks through its uppe ing and cont-act to ground at t ic sp Relay 64rconnects the tip and rii of the line through the baci: contacts ot relay 65, conductor 87, outer right bach' Contact of relay 66, Vlett Winding of relay 67 to the negative pole ci" battery 85. Assuming the call was initiated at the substation ifi-1, the test circuit entends over the tip andring conduct-ors through the substation eleinei coil to the device e8. T ie polarity of the device e8 is such that current flows theretl rough and accordingly the relay 67 operates. Relay 67 locks through its right Winding and contact ground at the vsequence switch spring 77.

l/Vhen the interrupter 69 shifts its contacts, a circuit is closed from ground through the lower contacts ot' said inte rupter, loxver contact ot relay 64h, lower back Icontact ct relayV 65, let't Winding ot-relay 66 to battery. Relay 66 locks through its right Winding and Contact tothe spring 7%. Relay disemi-r nectsV the test circuit troni the relay 67 and connects it to the lett Winding ot relay Since the polarity ot the battery 86 is opposite to the battery 85 current does not flow Vin the test circuit and accordingly relay 68 remains inert. f

Gn the nent shift ot the interrupter 69, a circuit is completed from ground through the upper contacts of said interrupter, spring 78, letttront contact or" relay 66, outer lett contact of relay 68, lower Winding ot relay to battery. Relay 65 operates and locks through its upper Winding and contact to the spring 74. Relay 65 disconnects he tip and Yring yconductors trom the conductor 87 and prepares a second test circuit including the relay 71. rihis test circuit may be traced rorn the negative pole of battery 88, 'through the lowerivinding of relay 71, upper tro tacts of relays 65 and 64, thence to the tip side ot the line L-1. Due to the polarity of the device 48 current tioyvs in this circuit and causes'the operation of relay 71. Relay 71 locks through its upper Winding and contact to the spring 77.

0n the nent shifting ot the interrupter 69, a circuit is closed from ground through the lower contacts thereof, lower contacts of relays and 65, spring 7 5 to the sequence switch magnet 70, thus drivin@ the sequence switch out of position 12 and into seine subsequent position, indicating thatpthe test has been completed. As the sequence switch leaves position 12, it opens the spring 7l and causes the release ot relays 64, 65 and 66.

When the called subscriber answers the re- 79 operates and a circuit is closed from ground through the spring 80, contact of relay 79, right Winding or" relay 72 to battery.

Relay 72 locks through its 'left Winding and contact to the spring 77.V` Y

, After conversation and While the sequence switch is passing from positions 15 to 17, a metering circuitis completed from battery through'the resistance 78, outer contact of relay 72, spring 76, outer right front contact of relay 67, inner lett contact of relay 68, mide dle vfront contact of relay 71, brush 68, through the Winding ot the register 81 to ground. Register 81 operates and charges the call to the substation A-l.

By inspetcing the circuits it Will be seen that When substation B-1 initiates a call the relay 67 operates the saine as in the case of substation A-l, Whereas relay 68 remains deenergized. When relay 71 is connected to the tip side or" the line, current does not flow troni the source 88 due to the device 52 the substation B-l. Accordingly, relay 7l remains deeneroized and themetering circuit eXtends as above traced through the middle back contact of relay 71, brush 62 and the register 82 to ground.

, lt substation @-1 initiates a call relay 67 does not operate, since negative vcurrent can`-` not flow through the device 58. Relay 68 does, however, operatedue to the polarity of battery 86. With relay67 deenergized and relay 68 operated, relay V65 operates in a circuit from battery through its lower Winding, outer left Contact of relay 67 and thence to ground through the yinterrupterY 69,V as above traced. Relay 65 connects the relay 71 to the tip side of the line. i Inthisinstance the test circuit may be traced from the battery 88 to the lower Winding of relayl, thence over the tip side of the line through the right Winding of the induction coil to the syvitchhoolr contacts through the talking transmitter and impulse sender and thence returning over the ring side of the line to the lower front contacts of relays 64 and 65 to ground. Relay 71 operates yin this circuit and locks and subsequently the metering circuit may be traced from battery through resistance 78, contact of relay 72, spring 76, outer right back contact yof relay 67, middle contact of relay v68, upper front contact of relay 71, brush 61, Winding 'of theregister 83 to ground'. V

lWhen the substation D-l initiates the call, relay 67 remains deenergized and relay 68 operates on the iirst test.- Gn the second test, however, relay 71 does not operate since negative current cannot flow through the device 57. Accordingly the metering circuit eX# tends as above traced through theupper contact ot' relay 71, brush 60, tothe Winding of the meter 84 to ground.

YVhile the invention has been illustrated in connection with systems cfa certain type, it will be understood that itis not so limited, but is applicable to various types of systems.

What is claimed is:

l. In a telephone system, a line having a plurality of substations, devices, one at each substation connected in series With the talking circuit and arranged to permit the flow of current in one direction but to resist the flow or' current in the opposite direction, and a test circuit including the conductors of said line. i

2. In a teleplione'system, a line having a plurality oit' substations, rectifying devices, one connected in series With the talking cir cuit at each substation and arranged to allow the flow ot current in one direction and to resist the flow of current in the opposite direction, and a test circuit including one side of the line and one of said devices.

8. The combination in a telephone system of a line having a plurality of substations, devices, one at each of said substations connected in series with the talking circuit tor permitting the loW of current in one direction and resisting its flow in the opposite direction, and test circuits, each including opposite sides of said line and one ot said devices.

4. The combination in a telephone system of a line having a plurality of substations, each substation being equipped With a device connected in series With the talking circuit and serving to permit the flow of current in one direction and to resist the loW of current in the opposite direction, and a test cir cuit including both sides of the line in parallel. v

5. In a telephone system, a line having a plurality of substations, devices, one at each substation connected in series With the talking circuit and arranged to permit the flow of test current in onedirection but to resist the flow of such current in the opposite direction, and a test rcircuit having one branch including one side of the line and a parallel branch including the other' side ot the line and one of said devices.

6. The combination in a'teleplione system of a party line,-devices at the substations for permitting current to flow in one direction and for resistingllovv in the opposite direction, certain of said devices being connected in parallel relation to the line conductors, other of said devices at a plurality of said stations being connected in series with the line conductors, and a test circuit including the conductors of said line.

7. In a telephone system, a line having a plurality of substations, each substation having a device connected in series with the talking circuit for permittingthe flow of current in one direction and resisting its flow in the opposite direction, a test circuit including the conductors of said line, a register, and means responsive to the flow of current in said test circuit for controlling the operation of said register.

8. In a telephone system, a line having a plurality of substations, each substation liaving a device connected in series with the talking circuit for permitting the lovv ot current in one direction and resisting its flow in the opposite direction, a test circuit including the conductors or' said line, registers, one for each substation, and means responsive to the flow of current in said test circuit for selecting and operating one of said registers.

9. In a telephone system, a party line, each of a plurality of stations on said line having a device in series With the talking circuit for permitting the flovv ,of current in one direction and resisting the iloWA of current in the opposite direction, means for making a numher of preliminary tests on said line to partially identify a calling station, and means dependent on said preliminary tests for making a further test to determine the calling station.

IO. In a telephone system, a party line, each of a pluralityy of stations on said line having a device in series With the talking circuit for permiting the flow yof current in one direction and resisting the flovv of current in the cpposite direction, means for making preliminary tests on said line by applying to the line sources of current of opposite polarity to partly identify a calling substation, and means dependent upon the result of said preliminary test for making a furthertest to completely identify the calling substation.

11. In a telephone system, a party line, each of a plurality of stations on said line having a device in series With the talking circuit for permitting the flow of current in one direction and resisting the lovv of current in the opposite direction, means 'for inakn ing a preliminary test over a circuit'including both sides of said line, and means dependent upon the result ofthe preliminary test for making a final test over one side of said line to identify a calling substation. c f

l2. In a telephone system, a party line,

each of a plurality of stations on saidline having a device in series With' the talking'r circuit for permitting the flow of current in one direction and resisting the flovv of current the result of the preliminary test toidentify the calling substation. l

In Witness whereof, I hereunto subscribe my name this 12th day of September, 1928.

RAYMOND E. COLLIS.

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